Conventional various robots such as a conveying robot, a welding robot, and a painting robot are used in a production site.
This kind of robot can include a brake, which prevents a component such as an arm from deviating from its normal position by its own weight, in some cases when a power source is blocked, for example. For example, Japanese Laid-open Patent Publication No. 2008-307618 discloses a robot that includes a non-excitation operation type electromagnetic brake of which the braking force is released by an electromagnetic force during power-on and the braking force is activated by a mechanical action of a spring or the like during power-off.
As described above, the conventional technology prevents a component such as an arm from deviating from its position by using a brake. However, the conventional technology has further room for improvement in that a component such as an arm can be more surely prevented from deviating from its position.
For example, one arm can be connected to the other arm via a speed reducer in some cases. In this case, when an input gear provided in an input shaft for inputting the rotation of a motor into the speed reducer is worn away due to aged deterioration, the posture of the arm is held in the state where the position of the arm is deviated by a wearing amount by which the input gear is worn away. For this reason, a posture-related calculation may not be secured of the posture holding position of an arm.
A conventional arm is beforehand prevented from deviating from its position by regularly performing the exchange of an input gear, for example. However, it is preferable to more surely prevent the position deviation of a component such as an arm.